一种用于数字图象传感器的彩色插值算法

A Color Interpolation Method for Digital Image Sensors

由于物理结构的限制 ,单片 CCD和 CMOS彩色图象传感器在每个像素的位置上只能采集一个颜色分量 ,其余两个颜色分量只能通过插值的办法得到 .鉴于通常的线性插值方法容易使图象的边缘变得模糊 ,并可能出现较为明显的颜色失真 ,而一些新方法尽管可以得到较高质量的插值图象 ,然而运算的复杂性限制了它们的应用 .为此提出了一种在色差空间进行插值的算法 ,以代替普通颜色空间的插值 ,同时用基于有理函数的插值算子来代替普通的线性算子 ,并通过后处理来进一步提高插值图象的质量 .由于色差空间的插值考虑了不同颜色分量间的耦合性 ,并利用了有理函数插值算子固有的边缘自适应特性 ,因而得到了较好的效果 .该方法另外的一个优点是计算速度较快 .实验结果表明 ,该该算法是有效的 .

Due to the physical structure of single-chip CCD or CMOS color image sensor, there is only a single color component at each pixel position. As a result, color interpolation or color demosaicing is required to reconstruct the other two color components. General linear interpolation method may blur the image edge, and introduce color artifacts near edges. Although state-of-art methods may increase image quality, the computational complexity limits their applications. This paper presents a novel color interpolation method. It effectively increases the quality of interpolated images in three ways. At first, it performs interpolation in color difference space rather then in normal color space. Secondly, it introduces Rational Functions (RF) based operator instead of linear operator. And at last, a post-processing step is employed further to enhance the image quality. Because interpolation in color difference space takes into account the correlations between each color components, and RF based operator is edge-adaptive, this is the reason why the image quality can be improved using this method. In addition, this method is simple and calculating efficient in contrast to some of the state-of-art methods. The experiments compare PSNR and PESNR as while as MSE with the other three methods at the end of this paper.